GCC starts complaining about possible pointer misalignment of pointers to the unpacked (alignment=4) structures in the packed (alignment=1) ones:
CC arch/x86/cpu/tangier/acpi.o arch/x86/cpu/tangier/acpi.c: In function ‘acpi_create_fadt’: arch/x86/cpu/tangier/acpi.c:22:37: warning: taking address of packed member of ‘struct acpi_fadt’ may result in an unaligned pointer value [-Waddress-of-packed-member] 22 | struct acpi_table_header *header = &(fadt->header);
CC arch/x86/lib/acpi_table.o arch/x86/lib/acpi_table.c: In function ‘acpi_create_spcr’: arch/x86/lib/acpi_table.c:366:37: warning: taking address of packed member of ‘struct acpi_spcr’ may result in an unaligned pointer value [-Waddress-of-packed-member] 366 | struct acpi_table_header *header = &(spcr->header);
Fix the potential issues by annotating embedded structures with __packed even though they are packed naturally.
Signed-off-by: Andy Shevchenko andriy.shevchenko@linux.intel.com --- arch/x86/include/asm/acpi_table.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/acpi_table.h b/arch/x86/include/asm/acpi_table.h index 02aea127c1..7588913f93 100644 --- a/arch/x86/include/asm/acpi_table.h +++ b/arch/x86/include/asm/acpi_table.h @@ -34,7 +34,7 @@ struct acpi_rsdp { };
/* Generic ACPI header, provided by (almost) all tables */ -struct acpi_table_header { +struct __packed acpi_table_header { char signature[4]; /* ACPI signature (4 ASCII characters) */ u32 length; /* Table length in bytes (incl. header) */ u8 revision; /* Table version (not ACPI version!) */